A composite molded article having a gas permeable membrane that is permeable to gas but is impermeable to liquid in a main body portion is used in various industrial fields. Such a composite molded article is used, for example, for preventing water droplets or dust from entering an enclosed space sealed by the main body portion at a part where the molded article is attached and for preventing moisture from staying in the enclosed space (namely, to ensure a ventilation). A so-called lamp cover for closing an opening formed in a lamp housing (a lamp holding portion) such as a head lamp or a tail lamp provided in a vehicle, which accommodates a light source body (a lamp, a bulb) of a lighting device, is a typical example of this kind of composite molded article. A connector case that accommodates various kinds of electronic device or a case cover for covering the case is another example of the composite molded article. A cultivating case for cultivating farm products such as mushrooms or a case cover thereof is another example of the composite molded article.
For example, JP-A-2005-71638 discloses a tubular component portion of a lamp housing, which has a gas permeable membrane (a filter) in a vent passage, as a composite molded article forming a haze preventing structure of a lighting device for a vehicle. Further, JP-A-2002-347068 discloses a molded article having a gas permeable membrane (a gas permeable sheet) connected to a vent opening formed in a cover body of a connector case. JP-A-2001-155814, JP-A-2003-63549 and JP-A-2003-152347 also disclose a usual technique related to a composite molded article having a gas permeable membrane.